MIDTERM DECK A Flashcards
What are the four basic pharmacokinetic processes? Hint: MOTIONAcronym: MADE
- absorption
- distribution
- metabolism
- excretion
MEtabolism + excretion = ___________
elimination
The movement of a drug from its site of administration into the blood?
absorption
Drug movement from the blood to the interstitial space of tissues and from there into cells (from blood to target)
distribution
AKA Biotransformation; enzymatically mediated alteration of drug structure.
Metabolism
Movement of drugs and their metabolites out of the body.
excretion.
What are the three ways a a drug can cross cell membranes?
- passage through channels or pores
- passage with aid of transport system
- direct penetration of the membrane itself.
In order to directly penetrate membranes, a drug must be ______ ______ .
Lipid Soluble (lipophilic) p.28Remember: Like dissolves like. If chemical is lipid soluble it can get through lipid membrane
The ____ of absorption is how soon effects will begin. The _____ of absorption helps determine how intense effects will be.
Rate;amount
Rate of dissolution, surface area, blood flow, lipid solubility and pH partitioning are all factors affecting _______.
absorption
The two common routes of drug administration are:
enteral and parenteral.
What is the difference between enteral and parenteral?
enteral is in the GI Tract. Parenteral is anywhere else. Usually means by IV,IM, SC.
Why does the site of drug administration matter? How does it change the effects?
The barriers to absorption associated with each route are different.
Does absorption take place when IV drugs are administered?
No. Absorption is the movement from site of administration INTO the blood. WIth IV, it goes directly into the blood.
What is the advantage to using IV for poorly soluble drugs?
The drugs can be dissolved in large volume of fluid and into the body through IV.
What is the recommended time for injecting a drug via IV? Why?
Over a 1 minute interval at least. It takes 15 second from arm to brain. We would have the chance to see any negative effects before emptying a syringe into the patient. p.33
What should you check for in IV solutions before administering drugs?
Check that drugs are in solution. If cloudy or contains particles, do not use!!!
What is the only barrier to absorption for IM administration?
the capillary wall; The same goes for SC (or SubQ)
What determines the absorption rate of IM administration?
- water solubility
2. blood flow at the site of injection.
If a drug is has poor solubility, even in IV solution, what method of administration can we use?
IM
What is a depot injection?
the administration of a sustained-action drug formulation that allows slow release and gradual absorption, so that the active agent can act for much longer periods than is possible with standard injections. Depot injections are usually given deep into a muscle.
What is a benefit to an IM Depot injection?
Long lasting means fewer injections
If your patient is on coumadin, warfarin or any other anticoagulant, can you give them IM medications?
No. The risk of bleeding is too high.
What are two barriers to absorption in the case of oral administration?
- GI Tract epithelial cells
2. Capillary Wall
The rate and extent of drug absorption following oral admistration can be highly variable due to:
- solubility (water vs fat soluble) and stability of drug
- gastric and intenstinal pH
- gastric emptying time
- _____________________
- other drugs in system (may be competing for binding proteins/receptors)
- coatings on the drug itself
Food in the gut.
What is the safest administration?
oral! no risk of fluid overload, infection or embolism, reversible.
A ______ is a mixture of a drug plus binders and fillers, all of which have been compressed together.
tablet
An ________-________preparation is covered with material designed to dissolve in the intestine, but not the stomach. Those materials used in the covering include fatty acids, waces and shellac.
Enteric-Coated
________ - _________ preparations are capsules filled with tiny spheres which contain the actual drug. The spheres have their own coatings. Why?
Sustained-Release; because the coatings dissolve at different times, allowing the drug to be released over time.
Drug distribution (movement of drugs throughout the body via the blood) is determined by three major factors:
- blood flow to tissues
- ability of drug to exit vascular system
- ability to enter cells
Why are abscesses and tumors resistant to drug therapy?
no blood supply in abscesslimited blood supply in tumor
Drugs enter into the blood and are transported where to exit the vascular system?
Capillary beds
Only drugs that are _____ ______ or have a _______ _____ can cross the BBB.
lipid soluble ; transport system
what protein in the blood binds to free drugs in the bloodstream?
plasma albumin
T or F: Hepatic metabolism always results in the breakdown of drugs into smaller molecules.
False, sometimes is synthesizes a molecule larger than the parent drug.
Drugs must be converted from ______-soluble to _______-soluble so that they may be excreted from kidneys. The most important consequence of drug metabolism is promotion of renal drug excretion.
lipid;water
A drug that is pharmacologically inactive as administered, but becomes active in the body after conversion.
Prodrug (p.39)….like provirus…sits around and waits.
List some reasons children under 1 are at risk with medication…
- BBB not fully developed
- liver not fully developed
- Kidneys are not full developed.
_______ is the process of stimulating enzyme synthesis.
induction p.39
How can malnutrition effect hepatic-drug metabolism?
poor diet may be missing important cofactors required for the drug to metabolize/function.p.40
The most important organ for drug excretion is the ______.
kidney
What are the three steps in renal drug excretion?
http: //www.youtube.com/watch?v=4X8pAizadWI
1. glomerular filtration (moves drugs from blood to urine)
2. passive tubular reabsorption (lipid soluble drugs move into blood)
3. active tubular secretion (tubular pumps organic acid /base from blood to urine)
What are some examples of nonrenal routes of drug excretion?
- Breast milk
- Bile (bile goes to small intestine, then our through feces)
- Lungs (anesthetics)
- Sweat and Saliva (in small amts)
If we administer two drugs that use the same transport system, will excretion of them be delayed? if so, why?
Yes, because the renal tubules are like revolving doors and can only carry a limited number of drug molecules per unit of time.
T or F: There is a direct correlation between therapeutic and toxic responses and the amount of drug present in plasma.
True. We can measure concentration in plasma instead of at the site (ie. can’t take sample from epileptic brain). p.43
Two plasma drug levels are super important:
- minimum effective concentration;
- ______ ______
toxic concentration
T or F: Concentration of drug must be at or above MEC.
TRUE; MEC = MINIMUM!
The _______ range is between the MEC and the toxic concentration.
Therapeutic Range
Which drug is harder to administer, one with a broad or narrow therapeutic range?
narrow. broad has more room to move within the range. With narrow you have very little room to error. The toxic concentration is too close to the MEC.
____ ___-___ is defined as the time required for the amount of drug in the body to decrease by 50%. Affects the potency for a medication.
Drug Half-Life
T or F: Regardless of the size of the dose, reaching the plateau takes the same amount of time for that particular drug.
True. The grams in the body would be greater, but the time it takes would not be different since it is always based on half-life (the time it takes to leave the body).
Fluctuations are seen between doses. The high concentration is called peak. The low concentration is the trough. How can we reduce fluctuations in drug levels?
- Administer by continuous infusion
- Administer depot preparation
- reduce the size of each dose and the dosing interval simultaneously.
The longer the half-life, the longer it takes to plateau. What can be done to reach the initial high level quicker upfront?
Administer a loading dose. By definition it is a large initial dose. p. 45
After the loading dose, _______ doses are given.
maintenance
T or F: It takes four half-lives for a drug to clear the body.
True. Each drug has it’s own individual half-life (length of time). It will take four of those to clear the system.
Avoirdupois 1kg = ___ lbs?
2.2 lbs
Gr stands for?
grain
dr stands for ?
dram
how many minims is 1 dram?
60 minims (60 minute drama on tv)
oz means?
ounce
how many ounces in a cup?
8 oz
how many cups in a pint?
2 cups
what does the symbol “T” stand for? How about “t”?
T = Tbspt= tsp
how many mL is 1 t?
5 ml
how many mL is 1T?
15 ml
how many pints to 1 quart?
2 pints
How many micrograms (mcg) to 1 gram?
1 million (1,000,000) mcg
how many grams to 1 kg?
1000g
The study of drugs in humans
Clinical Pharmocology
Use of drugs to diagnose, prevent, or treat disease or to prevent pregnancy. Also considered medical use of drugs.
Therapeutics (aka pharmacotherapeutics)
Any chemical that can affect the living processes.
Drug
Study of drugs and their interactions with living systems.
Pharmacology
What are the three most important characteristics that any drug should have?
Effectiveness (most important), Safety and selectivity.
Is there such thing as a safe drug?
No. All drugs have the ability to cause injury, esp with high dose and/or prolonged use.
How can we reduce the chance of adverse effects?
Proper drug selection and proper dosing.
What does selectivity mean?
A drug that elicits only the response it was given for (because it selects certain receptors).
- Selective drug action is possible largely because drugs act through specific receptors.
- If a drug interacts with only one type of receptor and if that receptor type regulates just a few processes, the drug will have limited effects. Conversely, if a drug interacts with several different receptor types, it is likely to elicit a wide variety of responses.
- Selectivity does not guarantee safety.
T or F: We want drugs to be reversible and predictable.
True.
What is the therapeutic objective?
To provide maximum benefit with minimum harm.
What factors determine the intensity of drug responses.
- Administration (dosage, time, route)
- Pharmacokinetics
- Pharmacodynamics
(In human body) Drug absorption, distribution, metabolism and excretion are four major ______ processes.
Pharmacokinetics
Impact of the drug on the body once it reaches its target site?
Pharmacodynamics
The _____ - ____ _____ refers to the rapid hepatic inactivation of certain oral drugs (liver metabolizes quickly). When the drug is absorbed from the GI tract, they are carried straight to the liver. If the capacity of the liver to metabolize the drug is high, the drug becomes completely inactivated with no therapeutic effect.
First Pass EffectFor a great short video:http://www.youtube.com/watch?v=QVCNfja7wkkhttp://www.youtube.com/watch?v=xiuWdJYyIKs
What can we do to circumvent (bypass) the first-pass effect?
administer the medication parenterally (under the tongue, through injection or IV). This allows it to reach therapeutic levels in the systemic blood and bypass the liver. Gets to the site of action before hitting the liver.
The study of the biochemical and physiologic effects of drugs and the molecular mechanisms by which those effects are produced. Simply put, the study of what drugs do to the body and how they do it?
Pharmacodynamics
____-_____ ______ is the relationship between the size of an administered dose and the intensity of the response produced.
dose-response relationship
Is the dose-response relationship graded or all-or-nothing? what is the importance of this?
Graded, which gives us more control and allows us to fit the needs of the patient. If it were all-or-nothing, and could only produce one intensity of response, we could not treat various patients with that drug.
_____ _____ is defined as the largest effect that a drug can produce. It is indicated by the height of the dose-response curve.
Maximum Efficacy
T or F: A drug with very high maximal efficacy is more desirable than a drug with lower efficacy.
False, we want to match the intensity of the response to the patient’s needs. Ex. Furosemide can cause dehydration because it is a high efficacy diuretic. We may choose a lower efficacy to reduce the intensity of volume of water to be mobilized.
The term ______ refers to the amount of drug we must give to elicit an effect.
potency; rarely an important drug characteristic. It is important to note that the potency of a drug implies nothing about its maximal efficacy. Potency and efficacy are completely independent qualities.
If morphine produces pain relief at a lower dose than meperidine, is it more potent or less potent?
more potent
Drugs are chemicals that interact with chemicals inside the body. ________ are the special chemicals in the body that produce effects. It is any functional macromolecule in a cell to which a drug binds to to produce effects.
Receptors
The binding of drugs to receptors can either _____ or ____ the action of the body’s own regulatory molecules.
mimic (agonist) or block (antagonist)
T or F: Drugs produce their therapeutic effects by helping the body use its pre-existing capabilities. Drugs cannot give cells new functions.
TRUE
There are four primary receptor families.
- Cell membrane embedded ______
- __ protein-coupled systems
- ligand-gated ____ channels
- transcription factors
- enzymes
- G
- ion
Transcription factors differ from other receptors in two ways.
- They are found _____ the cell rather than _____ the cell.
- Responses to activation of these receptors are _____ instead of _____.
p. 52
1. inside/within the cell rather than outside the membrane
2. delayed versus instant, or within milliseconds.
Transcription factors are situated in the nucleus on the DNA; therefore, they can only be activated by ______ that are ______ soluble.
ligands; lipid
The more selective a drug is, the fewer side effects it will produce. Why is that?
Selective drug action is possible because drugs act through specific receptors. p.52
_______ _______ Theory of drug-receptor interaction states that (1) the intensity of the response to a drug is proportional to the number of receptors occupied by that drug, and that (2) a maximal response will occur when all available receptors have been occupied.
Simple Occupancy Theory
